This invention relates to a quick-closing valve for the interruption of a fluid flow, in particular, for the interruption of the fuel supply to an aircraft gas turbine in the event of a shaft failure, which comprises a valve housing with a valve seat and a closing element and is incorporated in a fluid line via a fluid inlet and a fluid outlet port.
In many applications, it is necessary to interrupt a media flow as quickly as possible. In the case of jet engines, for example, a shaft failure, in particular the failure of the low-pressure turbine shaft, constitutes a considerable danger to persons and property. In the event of a shaft failure, the energy-producing side of the shaft, which is now detached from the energy-consuming side, will speed up in an uncontrolled manner. Consequently, the engine and the aircraft can be damaged or destroyed. In order to minimize the negative consequences of a shaft failure, it is first of all necessary to register this state as quickly as possible and then to interrupt the further supply of fuel in the shortest time possible on the basis of the signal indicating the shaft failure.
In a known apparatus employing mechanical means for the detection of a shaft failure, power transmission means of the mechanical type are also used for the interruption of the fuel supply, for example a wire rope. Apart from the demanding design and the susceptibility to wear, the time period required by a mechanical trigger to interrupt the fuel flow to the combustion chamber of the aircraft gas turbine is so long that consequential damages can occur.
In an electronic apparatus known from Patent Specification U.S. Pat. No. 4,712,372 for the detection of an overspeed condition and the interruption of the fuel supply, an electric signal is produced in the event of a shaft failure to electromagnetically actuate the closing element of the fuel shut-off valve. However, also with this system, the period from actuation of the solenoid until shut-off of the fuel supply by the closing element of the quick-closing valve is not short enough to safely avoid consequential damages resulting from driving the shaft part into overspeed until the valve responds. In this case, additional safety measures involving high design investment are required.